You did fine, Dave.
Brian’s suggestion of a PV diverter is the way to go. I have one of Robin Emley’s diverters
and used it for the same purpose you want the variable output inverter for. i.e. to avoid
backfeeding the grid.
At the time, I had a meter that tallied energy use only in one direction. (up)
By using the diverter, I heated a 55 gallon drum of water to “burn” excess energy produced
by my PV system. That kept it from flowing back through my meter and hence me getting
charged for it.
Diverter operation is automatic. When energy is needed by other loads, the diverter reduces its
diversion of excess energy - or stops diverting it altogether. When those loads no longer
need energy, diverter operation resumes. All transparent to the user, and essentially instantly.